Apparatus for edge-turning of covers on door panels



Aug. 25, 1964 E. G. 'GoLDsToNE 3,146,150

APPARATUS FoR EDGE-TURNING 0F COVERS oN DOOR PANELs Filed Nov. 14, 1960 5 Sheets-Sheet 1 F1 v INVENTOR. riz/J a/xffwc,

Aug. 25, 1964 E. G. GoLDsToNE 3,146,150

APPARATUS Foa EDGE-TURNING oF covERs oN DOOR PANELS Filed Nov. 14, 1960 5 Sheets-Sheet 2 In /d j; /M

INVENTOR. 67004727 6*'. Gags-2161er y Aug. 25, 1964 E. s. GoLDsroNE 3,146,150

APPARATUS FOR EDGE-TURNING OF COVERS oN DOOR PANELs Filed Nov. 14, 1960 5 Sheets-Sheet 3 WR im.. @-5- IN V EN TUR. Zin/4727 Ga .76 262.76.

Aug. Z5, 1964 APPARATUS FOR EDGE-TURNING OF COVERS ON DOOR PANELS Filed Nov. 14, 1960 E. G. GOLDSTONE 5 Sheets-Sheet 4 INVENTR. Z'wdf 6074?: 627e i 47m/KVS',

Aug. 25, 1964 E. G. GoLDsToNE 3,146,150

APPARATUS FOR EDGE-TURNING oF covERs oN DooR PANELS Filed NOV. 14, 1960 5 Sheets-Shea?l 5 United States Patent O 3,146,150 APPARATUS FR EDGE-TURNING F CVERS ON DOR PANELS Edward G. Goldstone, Huntington Woods, Mich., assigner to Allen Industries, Inc., Detroit, Mich., a corporation of Delaware Filed Nov. 14, 1960, Ser. No. 68,890 14 Claims. (Cl. 156-444) This invention relates to an edge-turning machine and more particularly to a machine for the edge-turning of covers on automobile door panels or the like to produce laminated panels.

Laminated panels of the type having a decorative sheet or cover on one face are in wide use. In the automotive industry interior door panels are often formed by covering one face of a rigid panel with a decorative cover of leather, cloth, plastic, or a combination of the same. In such structure the peripheral edges of the cover extend beyond the edges of the panel and are turned around the panel edges and secured by adhesive or lthe like to the opposite face of the panel so as to provide an attractive panel. The edge-turning of the cover has been done by hand for many years and some automatic machinery has been developed in an effort to perform this function quickly and inexpensively.

In such previous machines problems with respect to wrinkling of the cover during the edge-turning process occurred. In order to reduce wrinkling prior machines had a plurality of moving parts so that each part would move to carry out a particular phase of the overall operation requiring an excessive time period to elapse in the finishing of each laminated panel. Thus, the uni-t cost of such panels was greater than desired and the larger number of moving parts would at times fail to interact to achieve a satisfactory bonding of the turned edge portion of the cover tothe panel.

It is, therefore, an important object of this invention to provide an improved edge-turning machine which will automatically and quickly turn the edge portions of a cover over a panel unit to achieve a iirm bond between the cover and the panel unit without wrinkling the cover.

A further object of this invention is to -provide an improved machine for turning the edge portion of a cover on a panel having a singlemoving portion which folds the edge portion of the cover in a one-step automatic operation.

A still further object of this invention is to provide an improved edge-turning machine which has a single movable portion Which holds a panel unit and turns the edge portion of a cover thereon at the same time -by applying a vacuum induced pressure differential across the edge portion of the cover.

Another object of this invention is yto provide an improved edge-turning machine having a fast cycle of operation during which the edge portions-of a cover on a panel unit are turned around the panel unit to be firmly bonded thereto.

Still another object of this invention is to provide an improved `edge-turning machine which is inexpensive to build, has a long life, and is easily maintained.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims andthe accompanying drawing in which:

FIGURE 1 is a perspective View of a Amachine constructed in accordance with the principles of this invention;

FIGURE 2 is an .enlarged cross-sectional view taken along the head press of a machine-constructed in accordance with the principles of this invention;

ICE

FIGURE 3 is a View showing the relationship between apertures in a vacuum plate and the edge portion of a cover before turning;

FIGURE 4 is a front elevational View of a machine constructed in accordance with the invention;

FIGURE 5 is a side elevational View of the top portion of the apparatus shown in FIGURE 4;

FIGURE 6 is an enlarged cross-sectional view show.- ing a portion of the head press assembly during the evacuation phase of operation;

FIGURE 7 is a schematic View of the vacuum system in accordance with the principles of the present invention;

FIGURE 8 is a circuit which automatically controls the operation of the present invention;

FIGURE 9 is a cross section of a modified form of the xture plate holding means illustrated in FIGURE 2;

FIGURE l0 is a cross section of a modification of the head press illustrated in FIGURE 2; and

FIGURE ll is a cross section of a portion of the head press of FIGURE 10 when it is positioned away from a workpiece.

Referring now to FIGURE l, an edge-turning machine is illustrated in accordance with the principles of the invention having a support table generally designated 1) with a raised die generally designated 12 mounted thereon. A workpiece generally designated 13 is supported on .the raised die I2 and aligned therewith by pins 14 illustrated in FIGURE 6. Wing portions 15 extend from die 12 adjacent each corner thereof. The purpose of these wings will be set forth in the discussion of the machines operation. A top fluid power cylinder 16 having a .drive piston 1'7 therein is mounted on an overhung support generally designated 18 and moves a head press generally designated 2t) upwardly and downwardly with respect to table 10. A control panel 22 is mounted on the front of the support table 10 and regulates the machine through a complete cycle of operation.

In FIGURES 4 and 5 it can be seen that head press 20 is guided by vertical guide bars 24 and 26 which extend through guide bushings 27 on the support 18. Piston 17 moves head press 20 downwardly when fluid is supplied to cylinder 16 from a source (not shown) through a supply line 28 and a regulator valve 30 to a iiuid power cylinder inlet line 32. A solenoid actuated inlet valve 34 controls the fluid flow to the top and bottom of cylinder 16 depending on whether it is in an energized or deenergized position.

As head press 20 moves down, a trigger collar 36 on the vertical guide bar 24 will actuate a toggle limit switch 38 which energizes control circuitry in control panel 22 lto hold head press 20 in a down position against workpiece 13. Similar collars4 and 42 on vertical guide bar 26 will actuate toggle limit switches 44 and 46, Arespectively, at different points in the upward and downward movement of press 20. The purpose of these switches will be set forth in the discussion of the operation of the invention.

In FIGURE 2, the head press 20, comprises a head plate 48 and a rigid fixture plate 50. The head plate 48 is aligned with fixture plate 50 by dimples 51 and held thereto when permanent magnets 52 and 54 on head plate 48 are energized. A rubber diaphragm 56 is held between the head plate 48 and fixture plate 50.

In FIGURE 9, a mechanical interconnection is illustrated for holding the head plate to the fixture plate which represents a modification of the magnetic holding arrangement of FIGURE 2. A head plate 70, analogous to fhead plate 48, has a counterbore 72 which receives a bevelled diaphragm holder 74. A diaphragm 76 is disposed between the holder 74 and the head plate 70 and extends outwardly therefrom between the head plate 70 and a fixture plate 78, analogous to fixture plate 50, which has a counterbore 80 therein. Counterbore 80 receives a stud 82 having a bevelled head 84 which is fastened to fixture plate 78 by a nut 86 which is tightened thereagainst. Diaphragm holder 74 has an aperture 88 therein which receives the stud 82. A nut 90 on stud 82, when tightened, will draw fixture plate 78 against the diaphragm 76. A ring nut 92 is disposed on a shoulder 94 of the holder 74 for tightening it against diaphragm 76 to thereby achieve a sealing relationship between the holder 74, the head plate 70 and the diaphragm 76.

In both holding arrangements, the diaphragm S6 extends downwardly as illustrated in FIGURE 2 from between the head plate 48 and fixture plate 50 and extends over a seal 58 disposed below the peripheral edge of the head plate 48. The seal 58 is mounted in a channel 60 which is disposed on the underside of head plate 48 at the peripheral edge thereof. The head plate 48 has apertures 61 therein that receive a plurality of straps 62 which are connected to channel 60. The straps 62 in turn are detachably carried by toggle pins 63 which are adjustably attached to head plate 48. When the toggle pins 63 are adjusted away from the straps 62, channel 60 will fall away from head plate 48. rl`hus, the peripheral edge of diaphragm 56 can be fixed to the head press 20 by inserting it between channel 60 and head plate 48. Replacement of a worn diaphragm 56 is easily and quickly accomplished by merely removing the channel 60 from the head plate 48 and de-energizing magnets 52 and 54 to remove fixture plate 50.

When the head pless 20 is against the workpiece 13, diaphragm 56 is spaced from the raised die 12 and the workpiece 13, which is illustrated in FIGURE 2 as having a panel portion 55 and a cover 57 with a peripheral edge portion 59, to define a passageway 64 around the outer periphery of the raised die 12. The passageway 64 is sealed by the seal 58 which presses diaphragm 56 against the top of table 10. A vacuum plate 66 forms the top of die 12 and has apertures 67 extending therethrough to the outer peripheral edges thereof to connect the passageway 64 with an outlet 68 in the top of support table 10. A bottom plate 69 of die 12 may have smooth fillet portions 71 to minimize the stretch of diaphragm 56 when the passageway 64 is evacuated. A block 73 of suitable material such as wood is removably disposed between plates 66 and 69 to permit height adjustment of the die 12 to adapt the unit to different sized workpieces.

The fixture plate 50 is of the same size and shape as workpiece 13 and when head press 20 is against workpiece 13 said plate will completely overlie the workpiece 13. Thus, during the evacuation phase of the machines operation, which will be described later, the rigid fixture plate 50 will prevent the pressure differential across diaphragm 56 caused by atmospheric pressure on one side and a vacuum on the other from buckling the periphery of the workpiece 13.

In cases where the workpiece 13 is strong enough to resist edge-buckling caused by the pressure differential across the diaphragm 56, the fixture plate 50 and the permanent magnets 52 and 54 can be omitted. Such a case is illustrated in FIGURES and 11 wherein the periphery of a resilient diaphragm 200 is held against a head plate 202 by a channel 204 which extends around the periphery of the head plate 202. The channel 204 is removably fastened to head plate 200 by straps 206 which are fixedly attached to the channel 204 and toggle pins 208 which detachably extend through the straps 206 and are adjustably fastened to the head plate 202. The diaphragm 200 extends across a seal member 210, received by the channel 204, in a drum head-like fashion. When the head plate 202 is moved against the workpiece 13 the seal member 210 will bear against diaphragm 200 to form a sealed edge between the diaphragm 200 and the table 10. In this position, diaphragm 200 will extend across workpiece 13 to channel 204 to define the passageway 64 around the outer periphery of the raised die 12. The drum head-like fashion in which diaphragm 200 extends across the seal member 210 is best illustrated in FIGURE ll showing the disposition of diaphragm 200 before the head plate 202 moves toward workpiece 13. Once head plate 202 approaches workpiece 13, diaphragm 200 will stretch over the workpiece 13 as illustrated in FIGURE 10.

As shown in FIGURE 7, the outlet 68 communicates with a vacuum regulator valve 96 which is connected to a suitable vacuum source such as a vacuum pump 98. A vacuum valve cylinder 100 actuates the vacuum regulator valve 96 to an open and closed position. The cylinder 100 has a piston 102 and a solenoid actuated inlet valve 104 which controls the fiow of fluid from a line 106 connected to uid supply line 28. Fluid will fiow to the right or left end of cylinder 100 depending on whether valve 104 is in its energized or de-energized position. An arm on the piston extending from the cylinder unit 100 is arranged to trip the arm of a toggle switch 108 to move the switch 108 into an open position as the piston 102 moves to the left. (See also FIGURE 4.) The purpose of toggle switch 108 will be explained in the operation of the device. A line 116 connected to the fluid supply line 28 supplies fluid to a solenoid valve 112 which is connected to outlet 68 by a line 114. Fluid fiow through valve 112 breaks the vacuum in passageway 64.

In FIGURE 8, the machines controls are illustrated and include an automatic circuit 120, a timer circuit 122 and a manual control circuit 124. The circuits are connected to a suitable source of current 126 through a line switch 128. The automatic circuit has a pair of normally open starting buttons 130 connected in series with a relay 132 which is normally open, a coil 134 which actuates the inlet valve 34 and an emergency stop switch 136 which has normally closed and normally open contacts 137 and 139, respectively. Switch 136 is in series with the toggle limit switch 38 which is normally open and with the toggle limit switch 108 which is normally closed.

The toggle limit switch 46 is normally open and is in series with a relay 138 which is normally open. Relay 138 is serially connected to an electrical clutch 140 and a timer motor 142 in the timer circuit 122. The timer circuit 122 has a switch 144 which is normally closed and a switch 146 which is normally open. Switch 146 is serially connected when closed to a relay 148 which has a normally closed contact 150 and a normally open contact 152. The limit switch 44 is normally closed and is in series with the contact 152 of the relay 148 as well as a coil 154 which actuates the solenoid valve 112. Another coil 156 is connected in series with the limit switch 46 for controlling the uid inlet valve 104 to the vacuum valve cylinder 100. Selector switches 158, 160 and 162 are shown in the automatic position. If they are in the manual position all functions operate from buttons on the control panel 22. In the manual operation circuit, a normally closed up-button 164 is connected across a normally open opening button 166 which is connected across a normally closed closing button 168. When the up-button 164 is open coil 134 is de-energized causing the piston 17 to move the head press 20 upwardly. When the opening button 166 is closed the coil 156 is energized actuating inlet valve 104 to cause the vacuum valve 96 to be opened by piston 102 moving to the right. A normally open relay is connected in series with button 166 and is held through button 168 when energized to a closed position. Thus, when the closing button is opened the vacuum valve 96 will close since coil 156 will be de-energized causing piston 102 to move to the left. The emergency stop switch 136 operates on both automatic and manual.

The operation of the machine includes closing the line switch 128. Then an operator places the workpiece 13 on the raised die 12. For automatic operation selector switches 158, 160 and 162 will be placed in the automatic position illustrated in FIGURE 8. Then the operator presses start buttons 130 closed which causes relay 132 to be energized with its contacts assuming a closed position which causes the coil 134 in inlet valve 34 to be energized. This opens the inlet valve 34 causing fluid to flow into the top of cylinder 16 to drive piston 17 and press head 20 along with vertical guide bars 24 and 26 downwardly toward the workpiece 13 on the raised die 12. When the press head 20 contacts the workpiece 13, trigger collar 36 on vertical guide bar 24 Will have moved toggle limit switch 38 to a closed position. Relay 132 is then held through emergency stop switch 136 and toggle limit switch 38 Vthereby holding head press 20 in the down position since the coil 134 in the inlet valve 34 stays energized maintaining fluid pressure in the top of cylinder 16. Likewise, the toggle limit switch 46 is triggered closed by the collar 42 on the downstroke of head press 20 energizing relay 138 causing its contacts to assume a closed position. It is held through the normally closed contact 150 of relay 148. Closing of relay 138 energizes the clutch 140 and motor 142 in timer circuit 122 to begin a time cycle and also energizes the coil 156 which opens the inlet valve 104 to allow iiuid to enter the left side of the vacuum valve cylinder 100 causing the piston 102 therein to move to the right to open Vacuum valve 96. When head press 20 is in its down position diaphragm 56 will have formed the passageway 64 around raised die 12 and since vacuum valve 96 is open, passageway 64 will be evacuated by the vacuum pump 98. The diiferential pressure across diaphragm 56 will cause it to bear inwardly against the edge portion 59 causing it to turn to the rear of the panel 55. Figure 2 shows the initial shape that the diaphragm 56 assumes prior to evacuation of passageway 64.

FIGURE 6 shows the position the edge portion 59 will assume after diaphragm 56 is pressed thereagainst by the differential pressure thereacross when passageway 64 is evacuated. The diaphragm uniformly and positively turns the edge 59 of cover 57 to the backside of the panel -55 and then uniformly and positively presses the edge 59 against panel 55. A suitable pressure sensitive cement which is applied either to the backside of panel 55 or to the underside of edge 59 of cover 57 or both prior to the time the workpiece 13 is placed in the machine will then hold the edge 59 in a positive manner to panel 55.

The uniform turning action of diaphragm 56 around the periphery of the panel 55 prevents wrinkles from occurring in the cover while causing a firm bond between the edge portion 59 and the panel 55. In order to achieve such a uniform action the interaction between diaphragm 56 and the edge portion 59 at the corners of panel 55 should preferably be carefully controlled. The corners of edge portion 59 of cover 57 may be pie-cut as at 172 to help prevent binding and wrinkling in the edge portion 59 at the corners of panel 55. However, when the diaphragm 56 turns over the corners of panel 55 a forty-five degree fold occurs in the diaphragm. This fold may catch the edge portion 59 and hold it vertically so that it will not edge-turn. Consequently, there is no bonding between the edge portion 59 and the workpiece 13 at this point even though the corners of the edge portion 59 are pie-cut as at 172. The wing portions 15 of die 12 eliminate this problem and allow smooth turning of the edge portion S9 at the corners of the workpiece 13 by controlling the point where a fold will be formed, thus with a wing 15 on either side of the radius, a fold is formed thereover leaving the entire corner of the workpiece 13 free of fold. The wings 15 are so shaped that in spite of the web thereover, the edge portion 59 will be uniformly edge-turned to the rear side of the panel 55 by the diaphragm 56.

Timer circuit 122 allows suiiicient time in which passageway 64 can be evacuated through the vacuum valve 96 to assume a positive action by diaphragm 56. At

the end of a timing cycle the normally open switch 146 is closed which energizes relay 148 and thereby drops out the relay 138 and the timer circuit 122 since the normally closed contact 150 through which relay 138 is held assumes an open position. When relay 148 is energized, coil 154 is also energized opening solenoid valve 112 which permits liuid to enter passageway 64 breaking the vacuum therein. At this time the coil 156 in the inlet valve 104 of vacuum valve cylinder 100 is also de-energized. Fluid will then enter the right side of cylinder and vent from the left side of cylinder 100 as the piston therein moves to the left to close vacuum valve 96. As the air cylinder piston moves to the left, the toggle limit switch 108 is triggered open, topping out relay 132 which de-energizes coil 134 in the air valve 34 on top of fluid power cylinder 16. Air will then vent from the upper end of fluid power cylinder 16 as the piston 17 therein moves upwardly raising press head 20 away from workpiece 13. As press head Z0 moves upwardly, the toggle limit switch 44 is momentarily opened dropping relay 148 and coil 154 out of the circuit. Thus solenoid valve 112 is closed and relay 148 is in its de-energized position which permits the start of a second cycle of operation.

From the preceding detailed description, it is apparent that a machine of few moving parts is provided which will accurately and quickly turn edge portions over a work panel.

It will be understood that the specific embodiments of the improved edge-folding device which are herein disclosed and described are presented for purposes of eX- planation and illustration and is not intended to indicate limits of the invention, the scope of which is dened by the following claims.

What is claimed is:

1. In an edge-turning machine, support means for receiving a workpiece and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said support means, seal means mounted on said movable head means formed to bear against said support means when said movable head is against said workpiece, resilient diaphragm means completely overlying said workpiece and having a portion thereof disposed between said movable head and said seal means to define a sealed passageway around said workpiece when said movable head means is against said workpiece, and vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm means to bear against said workpiece to turn said peripheral edge portion around the edge of said workpiece.

2. In an edge-turning machine, support means having a die fixed thereon for receiving a workpiece, said workpiece having at least one corner portion and a cover lying thereover with a peripheral edge portion extending beyond the peripheral edge of said die so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said die, seal means mounted on said movable head means formed to bear against said support means when said movable head means is against said workpiece, resilient diaphragm means completely overlying said workpiece and having a portion thereof disposed between said seal means and said movable head to define a sealed passageway around said workpiece when said movable head means Vis against said workpiece, vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm means to bear inwardly against said workpiece to turn said peripheral edge portion around the edge of ysaid workpiece and means extending outwardly of said die below and adjacent the corner of said workpiece for engaging said inwardly `bearing resilient diaphragm means and forming folds therein adjacent the corner of said workpiece while leaving the portion of said diaphragm at the corner of said workpiece free of folds.

3. In an edge-turning machine, support means for receiving a workpiece, said workpiece having at least one corner portion and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said support means, seal means mounted on said movable head means formed to bear against said support means when said movable head means is against said workpiece, a resilient diaphragm carried by said movable head means completely overlying said workpiece and having a portion thereof positioned between said support means and said seal means to define a sealed passageway around said workpiece when said movable head means is against said workpiece, vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm means to bear against said workpiece to turn said peripheral edge portion around the edge of said workpiece, and rigid means bearing against said workpiece for preventing the workpiece from buckling under the force exerted thereon by said diaphragm.

4. In an edge-turning machine, support means having a die fixed thereon for receiving a workpiece, said workpiece having at least one corner portion and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said die so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said die, seal means mounted on said movable head means formed to bear against said support means when said movable head means is against said workpiece, resilient diaphragm means carried by said movable head for movement therewith completely overlying said workpiece and having a portion thereof positioned between said seal means and said support means to define a sealed passageway around said workpiece when said movable head means is against said workpiece, vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm means to bear inwardly against said workpiece to turn said peripheral edge portion around the edge of said workpiece, rigid means bearing against said workpiece for preventing the workpiece from buckling under the force exerted thereon by said diaphragm, and means extending outwardly of said die below and adjacent the corner of said workpiece for engaging said inwardly bearing resilient diaphragm means and forming folds therein adjacent the corner of said workpiece while leaving the portion of said diaphragm at the corner of said workpiece free of folds.

5. In an edge-turning machine, a die for receiving a panel and a cover lying thereover having a peripheral edge portion which extends outwardly of the periphery of the die so that the peripheral edge portion of said cover can be turned around the edge of said panel, movable head means for holding said panel against said die, seal means disposed on said movable head means, means releasably connecting said seal means to said movable head means, resilient diaphragm means carried by said movable head means completely overlying said workpiece and having a portion thereof engageable therewith said seal means to define a sealed passageway around said die when said head means is against said panel, said die having apertures therein extending to its outer periphery to communicate with said passageway, vacuum means communicating with said apertures for evacuating said passageway thereby causing said resilient diaphragm means to bear against said panel to turn said peripheral edge portion around the edge of said panel.

6. In an edge-turning machine, a die for receiving a panel, said panel having at least one corner portion and a cover lying thereover having a peripheral edge portion which extends outwardly of the periphery of the die so that `the peripheral edge portion of said cover can be turned around the edge of said panel, movable head means for holding said panel against said die, seal means disposed on said movable head means, means for releasably connecting said seal means to said movable head means, resilient diaphragm means carried by said movable head means completely overlying said panel and having a portion thereof engageable with said seal means to define a sealed passageway around said die when said head means is against said panel, said die having apertures therein extending to its outer periphery to communicate with said passageway, vacuum means communicating with said apertures for evacuating said passageway thereby causing said resilient diaphragm means to bear inwardly against said panel to turn said peripheral edge portion around the edge of said panel, and means extending outwardly of said die below and adjacent the corner of said panel for engaging said inwardly bearing resilient diaphragm means and forming folds therein adjacent the corner of said panel while leaving the portion of said diaphragm means at the corner of said panel free of folds.

7. In an edge-turning machine, a die for receiving a panel and a cover lying thereover having a peripheral edge portion which extends outwardly of the periphery of the die so that the peripheral edge portion of said cover can be turned around the edge of said panel, movable head means for holding said panel against said die, seal means disposed on said movable head means, means for releasably connecting said seal means to said movable head means, resilient diaphragm means carried by said movable head means completely overlying said workpiece and having a portion thereof engageable with said seal means to define a sealed passageway around said die when said head means is against said panel, said die having apertures therein extending to its outer periphery to communicate with said passageway, vacuum means communicating with said apertures for evacuating said passageway thereby causing said resilient diaphragm means to bear against said panel to turn said peripheral edge portion around the edge of said panel, and rigid means bearing against said panel for preventing the panel from buckling under the force exerted thereon by said diaphragm.

8. In an edge-turning machine, a die for receiving a panel, said panel having at least one corner portion and a cover lying thereover having a peripheral edge portion which extends outwardly of the periphery of the die so that the peripheral edge portion of said cover can be turned around the edge of said panel, movable head means for holding said panel against said die, seal means disposed on said movable head means, means for releasably connecting said seal means to said movable head means, resilient diaphragm means carried by said movable head means Completely overlying said panel and having a portion thereof engageable with said seal means to define a sealed passageway around said die when said head means 1s against said panel, said die having apertures therein extending to its outer periphery to communicate with said passageway, vacuum means communicating with said apertures for evacuating said passageway thereby causing said resilient diaphragm means to bear inwardly against said panel to turn said peripheral edge portion around the edge of said panel, means extending outwardly of said die below and adjacent the corner of said panel for engagmg said inwardly bearing resilient diaphragm means and forming folds therein adjacent the corner of said panel while leaving the portion of said diaphragm at the corner of said panel free of folds, and rigid means bearing against said panel for preventing the panel from buckling under the force exerted thereon by said diaphragm.

9. In an edge-turning machine, support means for receiving a workpiece and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, a movable head plate for holding said workpiece against said support means, a channel disposed adjacent the periphery of said movable head plate, means on said head plate for releasably connecting said channel thereto, said channel formed to bear against said support means when said head plate is against said workpiece, a resilient diaphragm carried by said head plate completely overlying said workpiece and having a portion thereof positioned between said channel and said support means to dene a sealed passageway around said workpiece when said head plate is against said workpiece, and vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm to bear against said workpiece to turn said peripheral edge portion around the edge of said workpiece.

10. In an edge-turning machine, support means having a die xed thereon for receiving a workpiece, said workpiece having at least one corner portion and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said die so that the edge portion of said cover can be turned around the edge of said workpiece, a movable head plate for holding said workpiece against said die, a channel disposed adjacent the periphery of said head plate, means on said head plate for releasably connecting said channel thereto, said channel formed to bear against said support means when said head plate is against said workpiece, a resilient diaphragm carried by said head plate completely overlying said workpiece and having a portion thereof positioned between said channel and said support means to deiine a sealed passageway around said workpiece when said head plate is against said workpiece, vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm to bear inwardly against said workpiece to turn said peripheral edge portion around the edge of said workpiece, and means extending outwardly of said die below and adjacent the corner of said workpiece for engaging said inwardly bearing resilient diaphragm and forming folds therein adjacent the corner of said workpiece while leaving the portion of said diaphragm at the corner of said workpiece free of folds.

11. In an edge-turning machine, support means for receiving a workpiece and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, a movable head plate for holding said workpiece against said support means, a channel disposed adjacent the periphery of said head plate, means on said head plate for releasably connecting said channel thereto, said channel formed to bear against said support means when said head plate is against said workpiece, a resilient diaphragm carried by said head plate completely overlying said workpiece and having a portion thereof positioned between said channel and said support means to deine a sealed passageway around said workpiece when said head plate is against said workpiece, vacuum means connected through said support means for evacuating said passageway thereby causing said resilient diaphragm to bear against said workpiece to turn said peripheral edge portion around the edge of said workpiece, and rigid means bearing against said workpiece for preventing the workpiece from buckling under the force exerted thereon by said diaphragm.

l2. In an edge-turning machine, support means having a die xed thereon for receiving a workpiece, said workpiece having at least one corner portion and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said die so that the edge portion of said cover can be turned around the edge of said workpiece, a movable head plate for holding said workpiece against said die, a channel disposed adjacent the periphery of said head plate, means on said head plate for detachably holding said channel thereagainst, said channel formed to bear against said support means when said head is against said workpiece, a resilient diaphragm carried by said head plate completely overlying said workpiece and having a portion thereof positioned between said channel and said support means to define a sealed passageway around said workpiece when said head plate is against said workpiece, vacuum means connected through said supp'ort means for evacuating said passageway thereby causing said resilient diaphragm to bear inwardly against said workpiece to turn said peripheral edge portion around the edge of said workpiece, means extending outwardly of said die below and adjacent the corner of said workpiece for engaging said inwardly bearing resilient diaphragm and forming folds therein adjacent the corner of said workpiece while leaving the portion of said diaphragm at the corner of said workpiece free of folds and rigid means bearing against said workpiece for preventing the workpiece from buckling under the force exerted thereon by said diaphragm.

13. In an edge-turning machine, support means for receiving a workpiece and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said support means, first drive means including a cylinder and piston for moving said head means through a complete cycle of operation consisting of moving said head means against said support means, holding said head means against said support means and moving said head means away from said workpiece, seal means mounted on said movable head means formed to bear against said support means when said movable head means is against said workpiece, resilient diaphragm means carried by said movable head means completely overlying said workpiece and having a portion thereof positioned between said seal means and said support means to dene a sealed passageway around said workpiece when said movable head means is against said workpiece, valve means communieating with said passageway, second drive means including a cylinder and a piston for moving said valve means through opened and closed positions, vacuum means connected to said valve means for evacuating said passageway when said valve means is opened thereby causing said diaphragm means to bear against said workpiece to turn said peripheral edge portion around the edge of said workpiece, and control circuit means for actuating said iirst and second drive means to move said head means through a complete cycle of operation in timed relationship to the opening and closing of said valve means.

14. In an edge-turning machine, support means for receiving a workpiece and a cover lying thereover having a peripheral edge portion extending beyond the peripheral edge of said support means so that the edge portion of said cover can be turned around the edge of said workpiece, movable head means for holding said workpiece against said support means, rst drive means including a cylinder and piston for moving said head means through a complete cycle of operation consisting of moving said head means against said workpiece, holding said head means against said workpiece and moving said head means away from said workpiece, an annular seal means mounted on said movable head means formed to bear against said support means when said movable head means is against said workpiece, resilient diaphragm means carried by said movable head means completely overlying said workpiece and having a portion thereof positioned between said annular seal means and said support means to define a sealed passageway around said workpiece when said movable head means is against said workpiece, valve means communicating with said passageway, second drive means including a cylinder and piston for moving said valve means through opened and closed positions, vacuum means connected to said valve means for evacuating said passageway when said valve means is open thereby causing said diaphragm means to bear against said workpiece to turn said peripheral edge portion around the edge of said work- 1 1 1 2 piece, rst switch means for actuating said rst drive References Cited in the file of this patent means to cause said head means to move against said sup- UNITED STATES PATENTS port means, timer means` for controlling the period during 2,049,970 Mitchell Aug 4, 1936 which said valve means 1s open, and second switch means 2 77A 410 Davies Dec 18 1956 which opens when said valve means closes for actuating said rst drive means to cause said head means to move FOREIGN PATENTS away from said workpiece. 134,197 Australia Sept. 9, 1949 

1. IN AN EDGE-TURNING MACHINE, SUPPORT MEANS FOR RECEIVING A WORKPIECE AND A COVER LYING THEREOVER HAVING A PERIPHERAL EDGE PORTION EXTENDING BEYOND THE PERIPHERAL EDGE OF SAID SUPPORT MEANS SO THAT THE EDGE PORTION OF SAID COVER CAN BE TURNED AROUND THE EDGE OF SAID WORKPIECE, MOVABLE HEAD MEANS FOR HOLDING SAID WORKPIECE AGAINST SAID SUPPORT MEANS, SEAL MEANS MOUNTED ON SAID MOVABLE HEAD MEANS FORMED TO BEAR AGAINST SAID SUPPORT MEANS WHEN SAID MOVABLE HEAD IS AGAINST SAID WORKPIECE, RESILIENT DIAPHRAGM MEANS COMPLETELY OVERLYING SAID WORKPIECE AND HAVING A PORTION THEREOF DISPOSED BETWEEN SAID MOVABLE HEAD AND SAID SEAL MEANS TO DEFINE A SEALED PASSAGEWAY AROUND SAID WORKPIECE WHEN SAID MOVABLE HEAD MEANS IS AGAINST SAID WORKPIECES, AND VACUUM MEANS CONNECTED THROUGH SAID SUPPORT MEANS FOR EVACUATING SAID PASSAGEWAY THEREBY CAUSING SAID RESILIENT DIAPHRAGM MEANS TO BEAR AGAINST SAID WORKPIECE TO TURN SAID PERIPHERAL EDGE PORTION AROUND THE EDGE OF SAID WORKPIECE. 